package jalview.math;

import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;

import java.util.Arrays;
import java.util.Random;

import org.testng.annotations.Test;

public class MatrixTest
{
  @Test(groups = "Timing")
  public void testPreMultiply_timing()
  {
    int rows = 500;
    int cols = 1000;
    double[][] d1 = new double[rows][cols];
    double[][] d2 = new double[cols][rows];
    Matrix m1 = new Matrix(d1);
    Matrix m2 = new Matrix(d2);
    long start = System.currentTimeMillis();
    m1.preMultiply(m2);
    long elapsed = System.currentTimeMillis() - start;
    System.out.println(rows + "x" + cols
            + " multiplications of double took " + elapsed + "ms");
  }

  @Test(groups = "Functional")
  public void testPreMultiply()
  {
    Matrix m1 = new Matrix(new double[][] { { 2, 3, 4 } }); // 1x3
    Matrix m2 = new Matrix(new double[][] { { 5 }, { 6 }, { 7 } }); // 3x1

    /*
     * 1x3 times 3x1 is 1x1
     * 2x5 + 3x6 + 4*7 =  56
     */
    Matrix m3 = m2.preMultiply(m1);
    assertEquals(m3.rows, 1);
    assertEquals(m3.cols, 1);
    assertEquals(m3.value[0][0], 56d);

    /*
     * 3x1 times 1x3 is 3x3
     */
    m3 = m1.preMultiply(m2);
    assertEquals(m3.rows, 3);
    assertEquals(m3.cols, 3);
    assertEquals(Arrays.toString(m3.value[0]), "[10.0, 15.0, 20.0]");
    assertEquals(Arrays.toString(m3.value[1]), "[12.0, 18.0, 24.0]");
    assertEquals(Arrays.toString(m3.value[2]), "[14.0, 21.0, 28.0]");
  }

  @Test(
    groups = "Functional",
    expectedExceptions = { IllegalArgumentException.class })
  public void testPreMultiply_tooManyColumns()
  {
    Matrix m1 = new Matrix(new double[][] { { 2, 3, 4 }, { 3, 4, 5 } }); // 2x3

    /*
     * 2x3 times 2x3 invalid operation - 
     * multiplier has more columns than multiplicand has rows
     */
    m1.preMultiply(m1);
    fail("Expected exception");
  }

  @Test(
    groups = "Functional",
    expectedExceptions = { IllegalArgumentException.class })
  public void testPreMultiply_tooFewColumns()
  {
    Matrix m1 = new Matrix(new double[][] { { 2, 3, 4 }, { 3, 4, 5 } }); // 2x3

    /*
     * 3x2 times 3x2 invalid operation - 
     * multiplier has more columns than multiplicand has row
     */
    m1.preMultiply(m1);
    fail("Expected exception");
  }
  
  
  private boolean matrixEquals(Matrix m1, Matrix m2) {
    return Arrays.deepEquals(m1.value, m2.value);
  }

  @Test(groups = "Functional")
  public void testPostMultiply()
  {
    /*
     * Square matrices
     * (2 3) . (10   100)
     * (4 5)   (1000 10000)
     * =
     * (3020 30200)
     * (5040 50400)
     */
    Matrix m1 = new Matrix(new double[][] { { 2, 3 }, { 4, 5 } });
    Matrix m2 = new Matrix(new double[][] { { 10, 100 }, { 1000, 10000 } });
    Matrix m3 = m1.postMultiply(m2);
    assertEquals(Arrays.toString(m3.value[0]), "[3020.0, 30200.0]");
    assertEquals(Arrays.toString(m3.value[1]), "[5040.0, 50400.0]");

    /*
     * also check m2.preMultiply(m1) - should be same as m1.postMultiply(m2) 
     */
    m3 = m2.preMultiply(m1);
    assertEquals(Arrays.toString(m3.value[0]), "[3020.0, 30200.0]");
    assertEquals(Arrays.toString(m3.value[1]), "[5040.0, 50400.0]");

    /*
     * m1 has more rows than columns
     * (2).(10 100 1000) = (20 200 2000)
     * (3)                 (30 300 3000)
     */
    m1 = new Matrix(new double[][] { { 2 }, { 3 } });
    m2 = new Matrix(new double[][] { { 10, 100, 1000 } });
    m3 = m1.postMultiply(m2);
    assertEquals(m3.rows, 2);
    assertEquals(m3.cols, 3);
    assertEquals(Arrays.toString(m3.value[0]), "[20.0, 200.0, 2000.0]");
    assertEquals(Arrays.toString(m3.value[1]), "[30.0, 300.0, 3000.0]");
    m3 = m2.preMultiply(m1);
    assertEquals(m3.rows, 2);
    assertEquals(m3.cols, 3);
    assertEquals(Arrays.toString(m3.value[0]), "[20.0, 200.0, 2000.0]");
    assertEquals(Arrays.toString(m3.value[1]), "[30.0, 300.0, 3000.0]");

    /*
     * m1 has more columns than rows
     * (2 3 4) . (5 4) = (56 25)
     *           (6 3) 
     *           (7 2)
     * [0, 0] = 2*5 + 3*6 + 4*7 = 56
     * [0, 1] = 2*4 + 3*3 + 4*2 = 25  
     */
    m1 = new Matrix(new double[][] { { 2, 3, 4 } });
    m2 = new Matrix(new double[][] { { 5, 4 }, { 6, 3 }, { 7, 2 } });
    m3 = m1.postMultiply(m2);
    assertEquals(m3.rows, 1);
    assertEquals(m3.cols, 2);
    assertEquals(m3.value[0][0], 56d);
    assertEquals(m3.value[0][1], 25d);

    /*
     * and check premultiply equivalent
     */
    m3 = m2.preMultiply(m1);
    assertEquals(m3.rows, 1);
    assertEquals(m3.cols, 2);
    assertEquals(m3.value[0][0], 56d);
    assertEquals(m3.value[0][1], 25d);
  }

  @Test(groups = "Functional")
  public void testCopy()
  {
    Random r = new Random();
    int rows = 5;
    int cols = 11;
    double[][] in = new double[rows][cols];

    for (int i = 0; i < rows; i++)
    {
      for (int j = 0; j < cols; j++)
      {
        in[i][j] = r.nextDouble();
      }
    }
    Matrix m1 = new Matrix(in);
    Matrix m2 = m1.copy();
    assertTrue(matrixEquals(m1, m2));
  }

  /**
   * main method extracted from Matrix
   * 
   * @param args
   */
  public static void main(String[] args) throws Exception
  {
    int n = Integer.parseInt(args[0]);
    double[][] in = new double[n][n];
  
    for (int i = 0; i < n; i++)
    {
      for (int j = 0; j < n; j++)
      {
        in[i][j] = Math.random();
      }
    }
  
    Matrix origmat = new Matrix(in);
  
    // System.out.println(" --- Original matrix ---- ");
    // / origmat.print(System.out);
    // System.out.println();
    // System.out.println(" --- transpose matrix ---- ");
    Matrix trans = origmat.transpose();
  
    // trans.print(System.out);
    // System.out.println();
    // System.out.println(" --- OrigT * Orig ---- ");
    Matrix symm = trans.postMultiply(origmat);
  
    // symm.print(System.out);
    // System.out.println();
    // Copy the symmetric matrix for later
    // Matrix origsymm = symm.copy();
  
    // This produces the tridiagonal transformation matrix
    // long tstart = System.currentTimeMillis();
    symm.tred();
  
    // long tend = System.currentTimeMillis();
  
    // System.out.println("Time take for tred = " + (tend-tstart) + "ms");
    // System.out.println(" ---Tridiag transform matrix ---");
    // symm.print(System.out);
    // System.out.println();
    // System.out.println(" --- D vector ---");
    // symm.printD(System.out);
    // System.out.println();
    // System.out.println(" --- E vector ---");
    // symm.printE(System.out);
    // System.out.println();
    // Now produce the diagonalization matrix
    // tstart = System.currentTimeMillis();
    symm.tqli();
    // tend = System.currentTimeMillis();
  
    // System.out.println("Time take for tqli = " + (tend-tstart) + " ms");
    // System.out.println(" --- New diagonalization matrix ---");
    // symm.print(System.out);
    // System.out.println();
    // System.out.println(" --- D vector ---");
    // symm.printD(System.out);
    // System.out.println();
    // System.out.println(" --- E vector ---");
    // symm.printE(System.out);
    // System.out.println();
    // System.out.println(" --- First eigenvector --- ");
    // double[] eigenv = symm.getColumn(0);
    // for (int i=0; i < eigenv.length;i++) {
    // Format.print(System.out,"%15.4f",eigenv[i]);
    // }
    // System.out.println();
    // double[] neigenv = origsymm.vectorPostMultiply(eigenv);
    // for (int i=0; i < neigenv.length;i++) {
    // Format.print(System.out,"%15.4f",neigenv[i]/symm.d[0]);
    // }
    // System.out.println();
  }
}